CN110785866A

CN110785866A - Improved film encapsulation

Info

Publication number: CN110785866A
Application number: CN201880041661.5A
Authority: CN
Inventors: 元泰景; 崔寿永; 桑杰伊·D·雅达夫
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2017-07-25
Filing date: 2018-07-03
Publication date: 2020-02-11
Anticipated expiration: 2038-07-03
Also published as: CN110785866B; TWI737923B; CN115172631A; US20210210737A1; TW201921759A; KR20200010610A; US20190036085A1; WO2019022929A1; US11770964B2; KR20210147105A; KR102569956B1; KR102333217B1; US10991916B2

Abstract

A method of encapsulating an Organic Light Emitting Diode (OLED) is provided. The method includes generating a first plasma in a process chamber, the first plasma having a plasma density of at least 10 when an OLED device is positioned within the process chamber ¹¹cm ^‑3Electron density of (2). The OLED device includes a substrate and an OLED formed on the substrate. The method further comprises: pretreating one or more surfaces of the OLED and the substrate with a first plasma; depositing a first plasma comprising silicon and nitrogen over the OLED by generating a second plasma comprising silicon and nitrogen in the process chamberA barrier layer, the second plasma having at least 10 ¹¹cm ^‑3Electron density of (d); and depositing a buffer layer over the first barrier layer; and depositing a second barrier layer comprising silicon and nitrogen over the buffer layer by generating a third plasma comprising silicon and nitrogen in the process chamber.

Description

Improved film encapsulation

Technical Field

Embodiments described herein relate generally to a thin-film encapsulation (TFE) structure formed over a device on a substrate and a method of forming the same.

Background

Organic light emitting diode displays (oled displays) have recently received attention in display applications (display applications) in view of faster response time, larger viewing angle, higher contrast, lighter weight, lower power consumption and suitability for being formed on flexible substrates, compared to conventional Liquid Crystal Displays (LCDs) or plasma displays (plasma displays). In addition to organic materials used in OLED devices (OLEDs), a number of polymer materials have been used to develop small molecule, Flexible Organic Light Emitting Diode (FOLED) and Polymer Light Emitting Diode (PLED) displays. Many of these organic and polymeric materials are suitable for the fabrication of complex multi-layer devices (multi-layer devices) on a number of substrates, making them ideal for use in various transparent multi-color display applications, such as thin Flat Panel Displays (FPDs), electrically pumped organic lasers (electro-mechanically pumped organic lasers), and organic optical amplifiers (organic optical amplifiers).

OLED devices may have a limited lifetime characterized by electroluminescent efficiency (electroluminescence)And its driving voltage increases. One known cause of degradation of the performance of OLED devices is the formation of non-emissive black spots or regions (non-emissive dark spots or regions) within the OLED display due to moisture and/or oxygen ingress into the organic layers of the OLED devices. To this end, OLED devices are typically encapsulated using a thin film comprising one or more moisture-transport limiting transparent materials. The moisture and oxygen barrier properties of these film envelopes (film envelopes) are generally directly related to the thickness of the film envelope. Current thin film encapsulants (including barrier and buffer layers) typically have about the same value due to moisture and/or oxygen permeation (moisture and/or oxygen permeation) over the lifetime of the OLED device To about

To prevent degradation of the OLED device. Although it is used for

To about

Relatively thin, but when the OLED device is subjected to bending, folding, rolling or similar stresses, these thicknesses reduce the flexibility of the OLED device and may cause cracking.

Therefore, there is a need for an improved film envelope that avoids the above-mentioned problems and has the moisture and oxygen barrier properties of current film envelopes.

Disclosure of Invention

Embodiments of the present disclosure generally relate to improved methods of encapsulating organic light emitting diodes and related devices. In one embodiment, a method of encapsulating an Organic Light Emitting Diode (OLED) is provided. The method comprises the following steps: generating a first plasma in a process chamber, the first plasma having a plasma flow rate up toLess than 10 ¹¹cm ^-3Wherein the OLED device is positioned within the process chamber, the OLED device including a substrate and an organic light emitting diode formed on the substrate; pretreating one or more surfaces of an organic light emitting diode and a substrate with a first plasma, depositing a first barrier layer comprising silicon and nitrogen over the organic light emitting diode by generating a second plasma comprising silicon and nitrogen in a process chamber, the second plasma having at least 10 ¹¹cm ^-3The second plasma being generated after the first plasma; depositing a buffer layer over the first barrier layer; and depositing a second barrier layer comprising silicon and nitrogen over the buffer layer by generating a third plasma comprising silicon and nitrogen in the process chamber, the third plasma being generated after deposition of the buffer layer.

In another embodiment, a method of encapsulating an Organic Light Emitting Diode (OLED) device is provided. The method comprises the following steps: generating a first plasma comprising silicon and nitrogen; depositing a first portion of a first barrier layer comprising silicon and nitrogen over the organic light emitting diode using a first plasma; generating a second plasma comprising silicon and nitrogen; and depositing a second portion of the first barrier layer comprising silicon and nitrogen over the first portion of the first barrier layer using a second plasma, wherein the first plasma differs from the second plasma in density by at least a factor of 100.

In another embodiment, a method of encapsulating an Organic Light Emitting Diode (OLED) device is provided. The method comprises the following steps: generating a first plasma comprising silicon and nitrogen in a first process chamber; depositing a first portion of a first barrier layer comprising silicon and nitrogen over the organic light emitting diode using a first plasma; generating a second plasma comprising silicon and nitrogen in a second process chamber; depositing a second portion of the first barrier layer comprising silicon and nitrogen over the first portion of the first barrier layer using a second plasma, wherein the first plasma differs from the second plasma in density by at least a factor of 100; depositing a buffer layer over the first barrier layer in a third process chamber; and depositing a second barrier layer over the buffer layer in a fourth process chamber, wherein the first process chamber, the second process chamber, the third process chamber, and the fourth process chamber are arranged around a single transfer chamber.

Drawings

So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

Fig. 1 is a side cross-sectional view of an OLED device including an organic light emitting diode and an encapsulation layer (encapsulating layer) formed over the organic light emitting diode according to embodiments described herein.

FIG. 2A is a schematic cross-sectional view of an exemplary process chamber, according to one embodiment.

Figure 2B illustrates a plan view of a portion of a feature of the process chamber illustrated in figure 2A, according to one embodiment.

Fig. 2C is a cross-sectional view of one of the plurality of antennas depicted in fig. 2B, according to one embodiment.

Fig. 2D is a process flow diagram of a method of encapsulating an Organic Light Emitting Diode (OLED) using the encapsulant of fig. 1, according to one embodiment.

Fig. 3A is a side cross-sectional view of an OLED device including the organic light emitting diode of fig. 1 and an encapsulant formed over the organic light emitting diode, according to another embodiment.

FIG. 3B is a schematic plan view of a cluster tool that can be used to form an encapsulant over the organic light emitting diode of the OLED device of FIG. 3A, according to one embodiment.

Fig. 3C is a process flow diagram of a method of encapsulating an organic light emitting diode using the cluster tool of fig. 3B and using the encapsulant of fig. 3A, according to one embodiment.

Fig. 4A-4I show comparative measurements of barrier properties and other properties of a silicon nitride layer deposited using a high-density plasma chemical vapor deposition (HDP-CVD) process according to embodiments described herein and a silicon nitride film (silicon nitride films) deposited using a conventional Capacitively Coupled Plasma (CCP) Plasma Enhanced Chemical Vapor Deposition (PECVD).

Figures 5A-5F illustrate the effect of biasing the substrate support to affect the properties of a silicon nitride layer deposited using a high density plasma chemical vapor deposition process.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. The drawings referred to herein should not be understood as being drawn to scale unless specifically indicated. Furthermore, the drawings are often simplified and some details or components are omitted for clarity of presentation and explanation. The drawings and discussion are intended to explain the principles discussed below and like reference numerals refer to like elements.

Detailed Description

Embodiments of the present disclosure include a method and related apparatus for forming an improved encapsulation for an Organic Light Emitting Diode (OLED) device. The following packages have a reduced thickness (reduced thickness) compared to conventional OLED packages, yet still effectively block the ingress of water and oxygen to avoid damaging the formed OLED device. This reduced thickness increases yield during manufacturing while also providing OLED devices with greater flexibility and durability compared to OLED devices having thicker encapsulants or encapsulant structures.

Fig. 1 is a side cross-sectional view of an OLED device 100 including an organic light emitting diode 102 and an encapsulant 111 formed over the organic light emitting diode 102, according to embodiments described herein. The OLED device 100 includes a substrate 106 and an organic light emitting diode 102 formed on the substrate 106. The organic light emitting diode 102 may be formed by a series of depositions using a mask. Typically, the substrate 106 may be formed of glass, metal (e.g., copper or stainless steel), or a polymeric material. For example, in some embodiments, the polymer substrate is composed of a thin flexible polymer sheet (pin), such as a thin Polyimide (PI), polyethylene terephthalate (PET), or polyethylene naphthalate (PEN). The OLED device 100 may further include a contact layer 108 disposed between the organic light emitting diode 102 and the substrate 106. The contact layer 108 includes a transparent conductive oxide such as indium tin oxide (ito), indium zinc oxide (izo), or tin oxide (izo).

During the normal lifetime of the formed OLED device, the Encapsulant 111 is a Thin-film Encapsulant (TFE) formed over the organic light emitting diode 102 to protect the OLED device 100 from performance degradation caused by exposure of the organic light emitting diode 102 to moisture and/or oxygen. The encapsulant 111 may include a first barrier layer 110, a buffer layer 112, and a second barrier layer 114. In other embodiments, the encapsulant 111 may include a plurality of buffer layers and more than two barrier layers, where each buffer layer is disposed between two barrier layers, such as buffer layer 112 disposed between barrier layers 110 and 114. In some embodiments, at least one of the barrier layers 110, 114 uses a high density plasma (i.e., has at least 10 a) ¹¹cm ^-3Plasma of electron density) as will be described in more detail below. In still other embodiments, one or more barrier layers 110, 114 may comprise two or more portions, where each portion is formed by a plasma having a different density (e.g., a first portion using a plasma having at least 10 a) ¹¹cm ^-3Is formed by a high density plasma having an electron density of, for example, about 10, and the second portion is formed by a plasma having an electron density of ⁹cm ^-3A lower-density plasma (low-density plasma) of a plasma of electron density), as will be described in more detail below. At least a portion of at least one of the barrier layers 110, 114 formed by the high density plasma improves the moisture and oxygen barrier properties relative to a portion of similar thickness formed by the lower density plasma.

The first barrier layer 110 may include a dielectric film (dielectric film), such as silicon nitride (SiN), silicon oxynitride (SiON), silicon dioxide (SiO), silicon nitride (SiO) ₂) Aluminum oxide (Al) ₂O ₃) Aluminum nitride (AlN), titanium oxide (TiO) ₂) Zirconium (IV) oxide, ZrO ₂) Or a combination of the foregoing. The buffer layer 112 may be an organic layer, such as a Hexamethyldisiloxane (HMDSO) layer, such as a fluorinated plasma polymerized HMDSO (pp-HMDSO: F) and/or a polymeric material including hydrogen, carbon and oxygen, wherein the polymeric material has a chemical formula C _xH _yO _zWherein x, y and z are integers. In other embodiments, the buffer layer material is selected from the group consisting of polyacrylate, parylene, polyimide, polytetrafluoroethylene, a copolymer of fluorinated ethylene propylene, perfluoroalkoxy copolymer resin, a copolymer of ethylene and tetrafluoroethylene, parylene, and combinations thereof.

At least one of the barrier layers 110, 114 may be formed using a high density plasma (i.e., having a thickness of at least 10 a) ¹¹cm ^-3Plasma of electron density) deposited barrier layer (e.g., silicon nitride layer), as will be described in more detail below. The barrier layers 110, 114 are spaced apart in the Z-direction (first direction) above the organic light emitting diode 102 (i.e., not on the sides of the organic light emitting diode 102). The barrier layer deposited using a high density plasma may have a thickness of about

To about

E.g. about in the Z-direction above the organic light emitting diode 102

To about

Is measured. Barrier layers in thin film encapsulants are typically formed using techniques such as Capacitively Coupled Plasma (CCP) processes, with lower density plasmas (i.e., having about 10 a) ⁹cm ^-3Plasma of electron density). Lower density plasmas formed during capacitively coupled plasma processes are generally used to achieve desired deposited film (e.g., uniformity, stress, etc.) and plasma characteristics (e.g., uniformity, reduced arcing (arc), etc.). In some embodiments, the density of the high density plasma used to form the at least one barrier layer (e.g., about 10 a) ¹¹cm ^-3Electron density) is greater than the density of the lower density plasma used to form the other barrier layer in the enclosure 111 (e.g., about 10 a) ⁹cm ^-3Electron density of) at least 100 times.

Encapsulants, including separate barrier and buffer layers, utilizing barrier layers formed using only conventional lower density plasmas generally need to be larger than

To obtain the moisture barrier and/or oxygen barrier properties of the barrier layer, e.g. less than 1x10 ^-4g/m ²Water Vapor Transmission Rate (WVTR) of day. However, for example, an encapsulant utilizing a silicon nitride barrier layer deposited using a high density plasma may have less than 1x10 ^- ⁴g/m ²Vapor transmission rate of day is less than

Total envelope thickness. In addition, compare with having at least

The respective silicon nitride barrier layers in the enclosures may be formed by high density plasmaAnd may have an approximate To about

Is, for example, about

To about

To yield an OLED device with higher flexibility. OLED devices including these thinner barrier layers are also less prone to cracking, improving the functionality and durability of the resulting OLED devices using barrier layers formed using high density plasmas, as compared to OLED devices containing barrier layers formed using lower density plasmas.

Figure 2A is a side cross-sectional schematic view illustrating a process chamber 200, according to one embodiment. Referring to fig. 1 and 2A, a process chamber 200 is illustrated. The process chamber 200 may be used to perform the deposition of one or more layers included in the enclosure 111 of fig. 1. In some embodiments, the process chamber 200 may be further used to pre-treat the OLED device 100 before the encapsulant 111 is formed over the organic light emitting diode 102. In one embodiment, the process chamber 200 may be used to form one or more barrier layers 110, 114 of an enclosure 111. One or more of the barrier layers 110, 114 may be a silicon nitride layer deposited according to the methods described herein.

The process chamber 200 is configured to process large area substrates, e.g., having a thickness greater than about 0.1m ²Of a surface area of, e.g., greater than about 2m ². The process chamber 200 is configured to process substrates oriented in a horizontal position. In other embodiments, the methods described herein are used in a process chamber that processes a substrate oriented in a vertical or substantially vertical position.

The process chamber 200 features one or more sidewalls 204, a lid 208, and a bottom 206, defining a processing volume 299. The processing volume 299 is fluidly coupled to a (fluid coupled to) vacuum (vacuum)209, such as one or more dedicated vacuum pumps. The process chamber 200 further includes a substrate support 210 disposed therein. The substrate support 210 includes a shaft (draft) 214 extending through the chamber bottom 206 that raises and lowers the substrate support 210 to facilitate transfer of the substrate 106 into and out of the process chamber 200.

The substrate 106 is loaded into the processing volume 299 through an opening 212 in one of the sidewalls 204, the sidewall 204 being conventionally sealed during deposition or other processes using a gate or slit valve (not shown). A plurality of lift pins (lift pins)216 are movably disposed through the substrate support 210 to transfer the substrate 106 toward the substrate support 210 or away from the substrate support 210. When the substrate support 210 is in the lowered position, a plurality of lift pins 216 extend onto the surface of the substrate support 210 to lift the substrate 106 for access by a robot handler (not shown). When the substrate support 210 is in the raised position, the plurality of lift pins 216 are positioned in the same plane or below the surface of the substrate support 210 and the substrate 106 is placed directly on the substrate support 210 for processing. The lift pins 216 may be moved by their lower ends contacting a fixed or movable pin plate (not shown). The substrate support 210 may further include a resistive heater 298 coupled to the controller 280 and the cooling fluid conduits 296, the controller 280 and the cooling fluid conduits 296 cooperating to control the temperature of the substrate 106 disposed on the substrate support 210 during deposition.

In some embodiments, an electrical bias may be provided to the substrate support 210 during processing, such as during deposition. The substrate support 210 may include a bias electrode 250 disposed on the substrate support 210 or in the substrate support 210. The bias electrode 250 is coupled to a bias power supply 255, the bias power supply 255 providing DC power, pulsed DC power, AC power, pulsed AC power, radio frequency power, pulsed RF power, or combinations thereof. In one embodiment, during deposition, the substrate support 210 is electrically biased by charging the bias electrode 250 to create a negative bias on the substrate support 210 and/or the substrate 106. In some embodiments, the substrate support 210 further comprises an electrostatic chuck electrode (not shown) on the substrate support 210 or in the substrate support 210. Typically, the electrostatic chuck electrode is coupled to a DC power to hold the substrate 106 on the electrostatic chuck electrode surface.

The process chamber 200 further includes a plurality of tubular gas distribution conduits (gas distribution conduits)221 and a plurality of antennas 233, each disposed above the substrate support 210 in the process chamber 200. A plurality of gas distribution conduits 221 may be used to distribute process gases from

gas inlets

222A, 222B into the processing volume 299. The plurality of gas distribution conduits 221 are located between the substrate 106 disposed on the substrate support 210 and the plane in which the plurality of antennas 233 are located. In one embodiment, each of the gas distribution conduits 221 may be separated from the surface of the substrate 106 by substantially the same vertical spacing (spacing distance), such as a vertical spacing between about 3000 mils and about 10000 mils. The plurality of holes 223 disposed in the gas distribution conduit 221 face the substrate 106 and provide a substantially uniform gas flow over the surface of the substrate 106.

In some embodiments, such as embodiments that form a silicon nitride barrier layer (e.g., barrier layer 110 in fig. 1), when used, the silicon precursor, the one or more nitrogen precursors, and the carrier gas (carrier gas) are mixed to flow together through the same gas distribution conduit 221. Each end of the gas distribution conduit 221 is coupled to a

respective gas inlet

222A or 222B to provide a more uniform pressure along the length of the gas distribution conduit 221, thereby flowing a more uniform gas flow out of the plurality of holes 223 disposed in the gas distribution conduit 221. In other embodiments, each of the precursor gases flows through a respective gas distribution conduit 221 before reaching the surface of the substrate 106 to prevent the precursor gases from reacting with each other.

The process chamber 200 enables a high-density plasma assisted chemical vapor deposition (high-density plasma assisted chemical vapor deposition) process using a plurality of antennas 233 disposed within the processing volume 299 and extending through the processing volume 299. In this embodiment, the high density plasma source is a linear microwave plasma source (LPS) (also referred to as antenna 233). However, the methods described herein may be used with any suitable high density plasma source, such as an Electron Cyclotron Resonance (ECR) plasma source or an Inductively Coupled Plasma (ICP) source. Importantly, these high density plasma deposition techniques can achieve high deposition rates (e.g., without any significant risk of arcing) when attempting to achieve similar deposition rates in capacitively coupled plasma chambers ) A significant risk of arcing may occur in capacitively coupled plasma chambers or elsewhere in radio frequency circuits (RF circuits). During plasma deposition, it is known that the occurrence of arcing can lead to unstable plasmas and non-uniform process results, and can even damage devices in manufacture. Here, a plurality of antennas 233 extend through a dielectric tube 237 (see fig. 2C), extending through the process chamber 200 to provide an internal volume across the process chamber 200 that is isolated from the processing volume 299 of the process chamber 200. Each antenna 233 is located in an antenna plane (antenna plane) between the chamber lid (chamber lid)208 and the planar arrangement (planar arrangement) of the plurality of gas distribution conduits 221. One or more microwave generators (microwave generators)230, each coupled to a power source 232, are coupled to one or both ends of each antenna 233. A cooling gas flow is provided to each antenna 233 from a cooling gas inlet 243, the cooling gas inlet 243 being coupled to a first end of each dielectric tube 237, and a cooling gas exhaust 245 being coupled to a second end of each dielectric tube 237. Typical cooling gases include clean dry air (clean dry air,CDA) with nitrogen (N) ₂)。

Fig. 2C is a cross-sectional view of one of the plurality of antennas 233 illustrated in fig. 2B, according to one embodiment. The antenna 233 generally includes a conductive stub 235 for radiating microwave energy into the processing space 299, the conductive stub 235 being surrounded by a dielectric tube 237, such as a quartz tube, substantially coaxial with the conductive stub 235. The electromagnetic wave from the stub 235 is radiated into the processing space 299 through the dielectric tube 237, where plasma of the process gas introduced from the plurality of gas distribution conduits 221 is formed.

According to one embodiment, FIG. 2B illustrates a plan view of some features of the process chamber 200 illustrated in FIG. 2A. A plurality of gas distribution conduits 221 are spaced apart from each other in a parallel arrangement (see substrate support 210 of fig. 2A) above the substrate 106 on the substrate support 210. Each gas distribution conduit 221 is located between two parallel antennas 233 of the plurality of antennas 233, the plurality of antennas 233 further being spaced apart from each other in a parallel arrangement above the substrate support 210 (fig. 2A).

Fig. 2D is a process flow diagram of a method 1000 of encapsulating the organic light emitting diode 102 with the encapsulant 111 of fig. 1, according to one embodiment. In the illustrated embodiment, the method 1000 is performed using the process chamber 200 of FIG. 2A. The method 1000 will be described below with reference to fig. 1 and 2A-2D.

At block 1002, a first plasma is generated over an organic light emitting diode 102 formed on a substrate 106, the substrate 106 disposed in a processing volume 299 of a process chamber 200. The first plasma may be of at least 10 ¹¹cm ^-3High density plasma of electron density. Generating the second plasma generally includes supplying a flow of a pre-treatment process gas (e.g., a single gas molecule or atom) to the processing volume 299 of the process chamber 200 and energizing the gas into a plasma to pre-treat the OLED 102 and the substrate 106. The first plasma pretreatment may improve interface properties (interfaces) between the oled 102 and the substrate 106 to improve adhesion when the first barrier layer 110 is formed on the oled 102 and the substrate 106. In thatIn some embodiments, the first plasma may be formed from a gas stream including nitrogen and/or hydrogen (e.g., nitrogen (N) gas ₂) Hydrogen (H) ₂) Ammonia (NH) ₃) Or dinitrogen monoxide (N) ₂O)), while in other embodiments the first plasma may be formed from an inert gas (e.g., helium or argon). In some embodiments, the generated plasma may depend on the type of substrate being used. For example, argon (Ar) plasma may be useful to increase adhesion to polyethylene terephthalate (PET) substrates or polyethylene naphthalate (PEN) substrates, while nitrogen (N) ₂) The plasma is more suitable for improving adhesion to the copper substrate. Furthermore, ammonia (NH) ₃) Plasma is more suitable for promoting adhesion of the glass substrate.

The flow rate of the pre-treatment gas to the chamber depends on the size of the substrate and the process chamber. For example, for a chamber sized to process 500mm by 730mm substrates, nitrogen (N) is included ₂) The total flow rate of the pretreatment gas of (a) can be between about 150sccm and about 3,000sccm, such as between about 250sccm and about 1,500sccm, such as between about 300sccm and about 900sccm, such as about 480 sccm. The first plasma may be formed by a linear microwave plasma source (LPS) 233. The linear microwave plasma source 233 may have power supplied across the conductive stub 235 at a frequency between about 1 gigahertz (GHz) and about 10GHz, such as about 2.45GHz or about 5.8 GHz. The power used depends on the size of the chamber, e.g., for a chamber sized for 500mm by 730mm substrates, the power may be set between about 500W and about 8000W, e.g., between about 500W and about 5000W, e.g., between about 1000W and 4000W. Suitable scaling (appropriating) may be used for chambers sized for other substrates, where the power setting is at about 130mW/cm ²About 2300mW/cm ²E.g. at about 130mW/cm ²About 1400mW/cm ²E.g. at about 270mW/cm ²About 1100mW/cm ²In the meantime. In other embodiments, the high density plasma may be formed from a plasma having a plasma density greater than that of the plasmaAn Inductively Coupled Plasma (ICP) source at a frequency between about 1MHz and about 20 MHz.

At block 1004, have at least 10 in maintenance ¹¹cm ^-3For a period of time, the oled 102 and one or more surfaces of the substrate 106 are pre-treated with the first plasma.

At block 1006, a second plasma is generated in the processing volume 299 of the process chamber 200. The second plasma may be of at least 10 ¹¹cm ^-3High density plasma of electron density. The gases provided to form the second plasma, which may include a silicon precursor gas and a nitrogen precursor gas, are flowed into the processing volume 299 of the process chamber 200 through a plurality of linear gas distribution conduits 221. The silicon precursor gas is any suitable silicon-containing gas, such as Silane (SiH) ₄) Disilane (Si) ₂H ₆) Trisilane (Si) ₃H ₃) Tetra-silane (Si) ₄H ₁₀) Silicon tetrafluoride (SiF) ₄) Silicon tetrachloride (SiCl) ₄) Dichlorosilane (SiH) ₂Cl ₂) Or mixtures of the above. The nitrogen precursor gas is any suitable nitrogen-containing gas, such as nitrogen (N) ₂) Ammonia (ammonia, NH) ₃) Diazene (N) ₂H ₂) Hydrazine (N) ₂H ₄) Or mixtures of the above. In some embodiments, a carrier gas is also provided, such as argon (Ar), hydrogen (H), for example ₂) Helium (He), derivatives thereof, or mixtures thereof. In one embodiment, Silane (SiH) ₄) Ammonium (ammonium, NH) ₄) And nitrogen (nitrogen, N) ₂) Co-flowed (co-flowed) through the plurality of linear gas distribution conduits 221 and into the processing space 299. Here, the silicon precursor gas and the nitrogen precursor gas are co-flowed to pass through the same linear gas distribution conduit 221. In other embodiments, precursor gases flow through individual gas distribution conduits 221 in order to preventPreventing the precursor gases from prematurely reacting in the gas distribution conduit 221.

The flow rate of the precursor gas to the chamber depends on the size of the substrate and the process chamber. For example, for a chamber sized to process 500mm by 730mm substrates, including Silane (SiH) ₄) The total flow rate of the silicon precursor gas of (a) is between about 150sccm and about 3,000sccm, such as between about 250sccm and about 1,500sccm, such as between about 300sccm and about 900sccm, such as about 480 sccm. Including ammonia (NH) ₃) The nitrogen precursor gas is flowed into the chamber at a flow rate of between about 1,200 seem and about 5,000 seem, such as between about 2,000 seem and about 4,000 seem, such as about 3,000 seem. When used, it includes argon (Ar) or nitrogen (N) ₂) The flow rate of the carrier gas of (a) is between about 450sccm and about 5,000sccm, such as between about 500sccm and about 3,500sccm, such as about 2,500 sccm. Suitable scaling may be used for chambers sized for other substrates where silane is present with ammonia (SiH) ₄:NH ₃) The gas flow ratio (gas flow ratio) of (a) may be between about 1:2 and about 1:6, for example about 1: 3. When argon is used, silicomethane is mixed with argon (SiH) ₄Ar) may be between about 1:1 and about 1:20, such as between about 1:5 and about 1: 10. When argon is used, ammonia is mixed with argon (NH) ₃Ar) may be between about 1:1 and about 1:10, such as between about 1:2 and about 1: 5. The chamber pressure is maintained below 1 Torr, such as between about 50 millitorr (mTorr) and about 250 mTorr, such as less than about 200 mTorr, such as less than about 125 mTorr. The substrate 106 may be separated from the linear gas distribution conduit 221 by a spacing between about 3000 mils and about 10000 mils (e.g., about 7000 mils).

By the linear microwave plasma source 233, the electron density is greater than about 10 ¹¹/cm ³The high-density plasma of (a) is formed using a carrier gas (when used), a silicon precursor gas and a nitrogen precursor gas. The linear microwave plasma source 233 may have power supplied across the conductive stub 235 at a frequency between about 1GHz and about 10GHz, such as about 2.45GHz or about 5.8 GHz. The power used depends on the size of the chamber, e.g. dimensioned for 500mm by 730mm substrate, the power may be set between about 500W and about 8000W, such as between about 500W and about 5000W, such as between about 1000W and about 4000W. Suitable scaling may be used for chambers sized for other substrates, where the power is set at about 130mW/cm ²About 2300mW/cm ²E.g. at about 130mW/cm ²About 1400mW/cm ²E.g. at about 270mW/cm ²About 1100mW/cm ²In the meantime. In other embodiments, the high density plasma may be formed by inductively coupled plasma source power (ICP) having a frequency between about 1MHz and about 20MHz, such as about 13.56 MHz.

At block 1008, a first barrier layer 110 comprising silicon and nitrogen is deposited over the organic light emitting diode 102 by maintaining the second plasma for a period of time. In one embodiment, the second plasma is maintained to form the first barrier 110, having about

To about

A thickness of, for example, about

To about For example about

Or about

As described above, the use of a high density plasma to form the first barrier layer 110 may result in a given thickness (e.g., a given thickness with improved moisture and oxygen barrier properties) compared to a same thickness barrier layer formed using a lower density plasma

) The barrier layer of (1). It is believed that at least a portion of the improved moisture and oxygen barrier properties of a barrier layer formed by a high density plasma as compared to a lower density plasma result from a reduced amount of damage to the barrier layer formed by the high density plasma, which has a lower rate of ion bombardment (ion bombardment) than the lower density plasma. The lower ion bombardment rate results in fewer pinholes (pin holes) in the formed barrier layer compared to a barrier layer formed by a lower density plasma, and the high density plasma results in a tighter (denser) layer being formed, both resulting in improved moisture and oxygen barrier properties of the barrier layer.

At block 1010, a buffer layer 112 is formed (e.g., deposited) over the first barrier layer 110. In one embodiment, the buffer layer 112 is formed of a Hexamethyldisiloxane (HMDSO) layer. In some embodiments, the buffer layer is formed in the process chamber 200, while in other embodiments, the buffer layer 112 may be formed in another process chamber.

At block 1012, a third plasma is generated in the processing volume 299 of the process chamber 200. The third plasma can be of at least 10 ¹¹cm ^-3High density plasma of electron density. In some embodiments, the third plasma is generated using the same or similar methods as described above with reference to generating the second plasma (i.e., the same gas, gas flow rate, power and frequency supplied from a linear microwave plasma source (LPS), pressure, temperature, etc.).

At block 1014, a second barrier layer 114 comprising silicon and nitrogen is deposited over the organic light emitting diode 102 by maintaining the third plasma for a period of time. In one embodiment, the third plasma is maintained to form a plasma having a thickness of about

To about

Of a second barrier layer 114, e.g. about To about

For example about

Or about

Although the second and third plasmas used to form the respective barrier layers 110, 114 are described as high density plasmas, in some embodiments, at least one of the barrier layers 110, 114 may be formed from a plasma having a lower density, e.g., about 10a ⁹cm ^-3The electron density of plasma (2) is, for example, capacitively coupled plasma. In some of these embodiments, the barrier layer formed by the lower density plasma may help reduce stress mismatch between the barrier layer and the buffer layer between the barrier layers. This reduced stress imbalance may help prevent encapsulant cracking when the OLED device is subjected to external stresses, such as bending.

According to another embodiment, fig. 3A is a side cross-sectional view of an OLED device 300 including an organic light emitting diode 102 and an encapsulant 311 formed over the organic light emitting diode 102. OLED device 300 is similar to OLED device 100 except that OLED device 300 includes an encapsulant 311 in place of encapsulant 111 described above. The enclosure 311 is similar to the enclosure 111 described above, except that the barrier layers 110, 114 from the enclosure 111 are replaced with barrier layers 310, 314. In addition, the encapsulant 311 additionally includes a second buffer layer 316 and a third barrier layer 318.

In some embodiments, the barrier layers 310, 314 may be the same as the barrier layers 110, 114 described above. In other embodiments, one or more barrier layers may be formed byThe portion formed with the high density plasma is formed with two portions of the second portion using a lower density plasma. For example, in the lower right side of fig. 3A, a close up (close up) of the barrier layer 310 is shown to include a first portion 310A and a second portion 310B. In one embodiment, the first portion 310A may use a high density plasma (i.e., have a density greater than about 10A) ¹¹cm ^-3Electron density plasma) and the second portion 310B may be formed using a lower density plasma (i.e., a plasma having about 10 a) ⁹cm ^-3Electron density of (2), e.g. about 5X 10 ⁷cm ^-3To about 5X 10 ⁹cm ^-3Electron density of).

Referring to barrier layer 110 of fig. 1, any portion formed using a high density plasma may be formed using the methods described above. The first portion 310A may have a thickness of about

To about A thickness of, for example, about To about

The first portion 310A and the second portion 310B may be formed of the same material, such as silicon nitride, but forming the portions 310A, 310B from plasmas having significantly different densities, such as differing by a factor of 100 or more, may alter many properties of the resulting portions 310A, 310B of the barrier layer. For example, in one embodiment, the first portion 310A may be deposited using a high density plasma to form a barrier layer portion (barrier) having tensile stress and improved water vapor transmission (i.e., lower water vapor transmission) while the second portion 310B may be deposited using a lower density plasma to form a barrier layer portion having compressive stress (compression) compared to a portion of the same thickness formed by a lower density plasmaPositive stress). The second portion 310B having a compressive stress may form an improved interface with the buffer layer 112 deposited over the first barrier layer 310 compared to the barrier layer portion having a tensile stress. Thus, the resulting barrier layer 310, including portions 310A, 310B, provides a barrier layer that is superior to a barrier layer formed by only a high density plasma or only a lower density plasma.

Although barrier layer 310 is shown to include two portions 310A, 310B, in other embodiments, the barrier layer may include additional portions formed using other combinations of high density plasmas and lower density plasmas, as well as portions formed from plasmas having other densities, such as barrier layers including three or more portions formed using at least three different plasmas, including high density plasmas (e.g., at least 10A) ¹¹cm ^-3Electron density of), medium density plasma (e.g., about 10) ¹⁰cm ^-3Electron density of) and lower density plasma (e.g., less than 10) ⁹cm ^-3Electron density of). Furthermore, although only barrier layer 310 is shown to include portions formed from plasmas having different densities, in some embodiments, one or more of barrier layers 314 and 318 may also include portions formed from plasmas having different densities.

The second buffer layer 316 may be similar to the buffer layer 112 described above with reference to fig. 1. For example, in some embodiments, the second buffer layer 316 is formed of the same material using the same method as described above for the buffer layer 112. Similarly, the second barrier layer 314 and the third barrier layer 318 may be similar to the first barrier layer 110 or the second barrier layer 114 described above with reference to fig. 1, or similar to the barrier layer 310 described with reference to fig. 3A. The enclosing member 311 may have about

To about

Of the substrate is described.

Fig. 3B is a schematic plan view of a cluster tool (cluster tool)350 that may be used to form the encapsulant 311 over the organic light emitting diode 102 of the OLED device 300 of fig. 3A, according to one embodiment. The cluster tool 350 includes a conveyor belt 351 leading to a transfer chamber 352. The cluster tool 350 further includes a first process chamber 361, a second process chamber 362, a third process chamber 363, a fourth process chamber 364, and a fifth process chamber 365. Each of the process chambers 361-365 may include a corresponding plasma source 371-375. The plasma source for a given process chamber may include, for example, a linear microwave plasma source, an electron cyclotron resonance plasma source, an Inductively Coupled Plasma (ICP) source, or a capacitively coupled plasma source. In some embodiments, the process chamber may include more than one plasma source, such as linear microwave plasma sources and capacitively coupled plasma sources.

The transfer chamber 352 may include robots (not shown) to transfer the substrates 106 in and out of each of the process chambers 361 and 365 and in and out of the conveyor 351. Environmentally controlled (environmentally controlled) transfer chamber 352 (e.g., vacuum and/or low water (H) ₂O) or oxygen (O) ₂) Ambient) may be used to transfer the substrate 106 to each of the different process chambers 361-365 such that each layer in the encapsulant 311 may be formed in series to encapsulate each oled 102 on each substrate 106. Although five process chambers are shown in cluster tool 350, in other embodiments, the cluster tool may include more or fewer process chambers, such as a dual process chamber tool in which one process chamber uses a high density plasma to form the barrier layer or portions of the barrier layer and another process chamber uses a lower density plasma to form the buffer layer and at least a portion of one barrier layer.

Each of the process chambers 361-365 may be a Plasma Enhanced Chemical Vapor Deposition (PECVD) chamber, wherein a portion of the process chambers 361-365 may be classified as high-density plasma chambers (e.g., may result in a PECVD chamber having a 10 degree plasma chamber) ¹¹cm ^-3Or higherThe sub-density plasma chamber, other process chamber 361 and 365 portions, may be more generally classified as a lower-density plasma chamber, for example, may be generated having a density of about 10 ⁹cm ^-3Of electron density, e.g. about 5X 10 ⁷cm ^-3To about 5X 10 ⁹cm ^-3Electron density of (2). The process chamber 200 described above with reference to fig. 2A using a linear microwave plasma source is an example chamber that may be used to generate a high density plasma chamber, but a plasma chamber including an Inductively Coupled Plasma (ICP) source or an Electron Cyclotron Resonance (ECR) plasma source may also be used to generate a high density plasma for forming the enclosure 311. An exemplary lower density plasma chamber may include a capacitively coupled plasma chamber.

In one embodiment, the first process chamber 361, the third process chamber 363, and the fifth process chamber 365 may be used to deposit a barrier layer or portions of a barrier layer using a high density plasma. For example, in this embodiment, the first process chamber 361 may be used to deposit the first portion 310A of the first barrier layer 310 and the second process chamber 362 may be used to deposit the second portion 310B of the first barrier layer 310 of the encapsulant 311. In addition, in this embodiment, the third process chamber 363 may be used to deposit the buffer layers 112, 316 of the encapsulant 311. Finally, the fourth process chamber 364 and the fifth process chamber 365 may be used to deposit the second barrier layer 314 and the third barrier layer 318, respectively, of the enclosure 311. In this embodiment, the first process chamber 361, the fourth process chamber 364, and the fifth process chamber 365 may be configured to form a high density plasma, while the second process chamber 362 and the third process chamber 363 may be configured to form a lower density plasma. For example, the first plasma source 371, the fourth plasma source 374 and the fifth plasma source 375 may be linear microwave plasma sources (LPS), and the second plasma source 372 and the third plasma source 373 may be Capacitively Coupled Plasma (CCP) sources.

Fig. 3C is a process flow diagram of a method 1100 of encapsulating an Organic Light Emitting Diode (OLED)102 by an encapsulant 311 of fig. 3A using the cluster tool 350 of fig. 3B, according to one embodiment. Method 1100 will be described below with reference to fig. 3A-3C.

At block 1102, the substrate 106 is transferred from the conveyor belt 351 into the first process chamber 361 through the transfer chamber 352. At block 1104, a high density plasma (first plasma) is generated in the first process chamber 361, and the first portion 310A of the first barrier layer 310 is deposited over the organic light emitting diode 102 using the high density plasma (first plasma). In some embodiments, the substrate and the organic light emitting diode may be pre-processed before performing block 1104 using the same or similar operations as described above with reference to block 1004 of fig. 2D.

At block 1106, the substrate 106 is transferred from the first process chamber 361 to the second process chamber 362 through the transfer chamber 352. At block 1108, a lower density plasma (second plasma) is generated in the second process chamber 362 and the second portion 310B of the first barrier layer 310 is deposited over the organic light emitting diode 102 using the lower density plasma (second plasma). The density of the lower density plasma in block 1108 (e.g., 10) ⁹cm ^-3) May differ from the density of the high density plasma in block 1104 by a factor of at least 100.

At block 1110, the substrate 106 is transferred from the second process chamber 362 to the third process chamber 363 through the transfer chamber 352. At block 1112, a lower density plasma (third plasma) is generated in the third process chamber 363, and the first buffer layer 112 is deposited on the first barrier layer 310 using the lower density plasma (third plasma).

At block 1114, the substrate 106 is transferred from the third process chamber 363 to the fourth process chamber 364 through the transfer chamber 352. At block 1116, a high density plasma (fourth plasma) is generated in the fourth process chamber 364 and the second barrier layer 314 is deposited over the first buffer layer 112 using the high density plasma (fourth plasma).

At block 1118, the substrate 106 is transferred from the fourth process chamber 364 to the third process chamber 363 through the transfer chamber 352. At block 1120, a lower density plasma (fifth plasma) is generated in the third process chamber 363 and the second buffer layer 316 is deposited over the second barrier layer 314 using the lower density plasma (fifth plasma).

At block 1122, the substrate 106 is transferred from the third process chamber 363 to the fifth process chamber 365 through the transfer chamber 352. At block 1124, a high density plasma (sixth plasma) is generated in the fifth process chamber 365 and the third barrier layer 318 is deposited over the second buffer layer 316 using the high density plasma (sixth plasma).

As shown in fig. 4A-4I,

methods

1000 and 1100 provide examples of forming an encapsulant over an Organic Light Emitting Diode (OLED) device with improved barrier properties to moisture and oxygen ingress therein to the underlying OLED device when compared to an encapsulant formed using only a conventional Capacitively Coupled Plasma (CCP) Plasma Enhanced Chemical Vapor Deposition (PECVD) deposition process. Fig. 4A-4I show comparative measurements of barrier properties and other properties of a silicon nitride layer deposited using a high-density plasma chemical vapor deposition (HDP-CVD) process, and a silicon nitride film deposited using a conventional Capacitively Coupled Plasma (CCP) Plasma Enhanced Chemical Vapor Deposition (PECVD) deposition, according to embodiments described herein.

Figures 4A-4B show the percentage (%) of silicon-hydrogen bonds (Si-H bonds) in figure 4A versus the percentage (%) of nitrogen-hydrogen bonds (N-H bonds) in figure 4B for silicon nitride layers formed using high density plasma chemical vapor deposition (HDP-CVD) and capacitively coupled plasma chemical vapor deposition (CCP-CVD) when these silicon nitride layers are maintained at 85 ℃ and 85% relative humidity from 0 hours to less than about 1500 hours. As can be seen from figure 4A,

the HDP layer of silicon nitride 415 and the high density plasma silicon nitride layer 417 was used at 0 hr ratio CCP silicon nitride layer 413 and

the capacitively coupled plasma silicon nitride layer 411 of (a) initially shows fewer silicon-hydrogen bonds, but the percentage (%) of silicon-hydrogen bonds in the CCP silicon nitride layers (CCP silicon nitride layers)411 and 413 decreases over time. While silicon-hydrogen bonding is not necessarily undesirable in a silicon nitride layer used as a barrier layer in a thin film encapsulation structure,

capacitively coupled plasma silicon nitride layer 413 and

the decrease in the percentage (%) of silicon-hydrogen (Si-H) of the capacitively coupled plasma silicon nitride layer 411 over time indicates that the silicon-hydrogen bonds are replaced by undesirable silicon-oxygen bonds (Si-O bonds). This shows the relative instability (relative instability) of the conventionally deposited capacitively coupled plasma silicon nitride layers 411 and 413 when compared to the HDP silicon nitride layers 415 and 417. Fig. 4B shows that both the high density plasma deposition and the CCP deposition are relatively stable with respect to the percentage (%) of nitrogen-hydrogen bonds over time.

Fig. 4C shows the percent (%) change in the concentration of silicon-nitrogen bonds in the deposited silicon nitride layer from 0 hours to less than about 1500 hours when exposed to 85 ℃ and 85% relative humidity. Fig. 4D shows the percent (%) change in the concentration of silicon-oxygen bonds in the deposited silicon nitride layer of fig. 4C over the same time period. The percentage change in concentration values in fig. 4C and 4D has been normalized. As can be seen in fig. 4C and 4D, the silicon-oxygen concentration of the deposited capacitively coupled plasma silicon nitride layers 411 and 413 increased over time and predictably resulted in a decrease in the silicon-nitrogen concentration in the deposited layers, while the high density plasma silicon nitride layer remained stable over the same time period with no to little noticeable shift in silicon-oxygen (Si-O) or silicon-nitrogen (Si-N), indicating that the high density plasma silicon nitride layer has excellent barrier properties to oxygen permeation (oxygen permeation) when compared to the capacitively coupled plasma silicon nitride layer.

Figures 4E-4G show fourier transform infrared (FTIR spectra) spectra of silicon nitride layers of a high density plasma (figure 4E) and a capacitively coupled plasma (figures 4F and 4G) after exposure to 85 ℃ and 85% relative humidity for 0 hours to about 1400 hours and increments therebetween. As shown in figure 4F of the drawings,

from 0 hours to about 1400 hours of exposure of the high density plasma silicon nitride layer shows little to no change in the concentration of the thin film. In particular, the observation of little to no change in the concentration of silicon-oxygen bonds and silicon-nitrogen bonds for 1400 hours shows

Without at least a minimum of undesired oxygen penetration of the high-density plasma layer. However, from measurements at 0 hours (420) to 1300 hours (426) and as can be seen in FIG. 4F, the conventional

The silicon nitride layer of (a) shows a measurable increase in the concentration of silicon-oxygen bonds. Since when compared with

The capacitively coupled plasma layer of (a) is,

shows a higher concentration of silicon-oxygen bonds at increasing time intervals, with possible oxygen penetration from 0 hours (420) to 680 hours (424), 820 hours(425) And 1300 hours (426) of exposure

Is even more perceptible. Figures 4E-4G show that a high density electrical plasma silicon nitride layer deposited according to embodiments of the present disclosure is an excellent barrier to oxygen penetration compared to a conventionally deposited capacitively coupled plasma silicon nitride layer.

Fig. 4H and 4I show the water vapor transmission rate of a silicon nitride layer exposed to 40 ℃ and 100% relative humidity, with the lower water vapor transmission rate showing the resistance of the silicon nitride layer to water penetration therein. FIG. 4I shows

Compared to the capacitively coupled plasma silicon nitride layer 413

Wherein the high-density plasma silicon nitride layer 417, wherein the high-density plasma layer has little to no change of about 1x10 between 0 hours and about 140 hours ^-4g/m ²Relatively stable water vapor transmission rate of day The capacitively coupled plasma silicon nitride layer 413 of (a) failed after about 120 hours, which no longer showed measurable resistance to water penetration. FIG. 4H shows a layer of a material deposited according to an embodiment of the present disclosure and having

And

over time and up to between about 140 hours and about 275 hours of a silicon nitride high density plasma layer (silicon nitride HDP layer)Water vapor transmission rate. Notably, the water vapor transmission rate of each high density plasma silicon nitride layer was stable over the measured time period.

It is also noted that the high density plasma and capacitively coupled plasma deposited silicon nitride layers have substantially similar transmittance and step coverage characteristics (. high density plasma films and capacitively coupled plasma films both have a transmittance greater than 90% at a wavelength of 400 nanometers (nm) and a step coverage factor greater than 0.85 over a step height pattern of 2.5 microns (μm.) HDP silicon nitride will also allow for desirably thinner barrier layers in Thin Film Encapsulation (TFE) structures, e.g., conventional capacitively coupled plasma silicon nitride layers in Thin Film Encapsulation (TFE) structures typically have a thickness between 0.5 μm and 1 μm or greater than 1 μm, as shown in fig. 4H-4I, when compared to the thickness of conventional capacitively coupled plasma silicon nitride layers in Thin Film Encapsulation (TFE) structures

A layer of capacitively coupled plasma silicon nitride (ccp silicon nitride),

the high density plasma silicon nitride layer has significantly improved barrier properties. This allows the silicon nitride barrier layer in the thin film encapsulation structure deposited using high density plasma to have a thickness of less than about

E.g. in the range of about

And about

E.g. in the range of

And about

E.g. in the range of

And

between or below about

Table 1 (shown below) and fig. 5A-5F illustrate that the effect of biasing the substrate support (biasing) may affect the properties of the silicon nitride layer of table 1 deposited using a high density plasma chemical vapor deposition (HDP-CVD) process. As can be seen in table 1, biasing the substrate support results in the deposition of a low pressure and/or compressive stress silicon nitride layer and maintains the improved barrier properties of a high density plasma chemical vapor deposition (HDP-CVD) silicon nitride layer as compared to a capacitively coupled plasma silicon nitride layer as seen in fig. 4A-4I. The process properties and resulting silicon nitride film properties illustrated in Table 1 use Silane (SiH) ₄) With ammonia (NH) ₃) Linear microwave plasma source high density plasma assisted chemical vapor deposition (high density plasma assisted CVD) of silicon nitride layers on substrates of 500mm by 730mm of precursor. The flow rate of the silane precursor is 480sccm and the flow rate of the ammonia precursor is 2700sccm, if used, and the silane precursor, ammonia precursor, and carrier gas are mixed prior to distribution into the chamber processing volume. For samples HD1 to HD14, no carrier gas flowed. Sample HD15 has an argon (Ar) carrier gas flow rate of 1350sccm and sample HD16 has nitrogen (N) of 1350sccm ₂) The gas flow rate. For each sample HD1-HD16, the substrate was initially heated to a processing temperature of 90 ℃. During deposition of samples HD3 through HD13, the substrate temperature was monitored and it was observed that the substrate reached temperatures as high as 155 ℃, however, it is understood that OLED devices would thermally degrade at process temperatures greater than about 100 ℃, while the substrate temperature should be maintained below about 100 ℃ during fabrication of TFE structures over pre-formed OLED devices. The frequency of the LPS power is 2.45 GHz. Table 1 shows film stress response to substrate support for high density plasma silicon nitride samplesA change in the bias of the member, wherein a positive stress value represents a tensile stress and a negative stress value represents a compressive stress.

TABLE 1

Fig. 5A-5F show the effect of the substrate Bias power (Bias set power) (W) on the barrier and other properties of a silicon nitride layer deposited using a linear microwave plasma source (LPS) high density plasma chemical vapor deposition method according to embodiments described herein. Fig. 5A-5F show silicon nitride layers deposited using rf power from linear microwave plasma sources of 2000W (2000 WMW as described in fig. 5A-5F), 2500W (2500W MW) and 3000W (3000W MW), wherein the rf power has a frequency of 2.45 GHz. Silicon nitride layers were deposited on 500mm by 730mm substrates using 2000W, 3000W and 5000W processes by biasing the substrate support with a power between 0W and 4000W using a 373KHz frequency RF power source. As can be seen in FIGS. 5A-5F, as the substrate bias power is increased from 0W to 4000W, the properties of the silicon nitride layer, including the Deposition Rate (DR), Refractive Index (RI), and Si-H concentration (Si-H%), remain substantially unchanged; while with increasing substrate bias power, a small increase in N-H concentration (N-H%) is seen, and a small decrease in Wet Etch Rate (WER) is seen. Notably, when 2500W to 4000W is applied to the substrate support, the high tensile Stress in the range from 100MPa (tensile) to 320MPa (tensile) is shifted to 150MPa (compressive) to 250MPa (compressive) by applying no bias power, and the film Stress (Stress) of the high density plasma deposited silicon nitride layer is tunable (tunable) based on the substrate support bias power. 4A-4I illustrate how high density plasma chemical vapor deposition can be used to form an effective silicon nitride barrier layer relative to a silicon nitride barrier layer formed using capacitively coupled plasma chemical vapor deposition (CCP-CVD); fig. 5A-5F illustrate how the desired stress values (stress levels) of the formed barrier layer can be obtained using capacitively coupled plasma chemical vapor deposition or high density plasma chemical vapor deposition by varying the bias voltage applied to the substrate support.

Thus, the data of FIGS. 4A-4I and FIGS. 5A-5F can be used to form an improved enclosure. For example, one or more barrier layers formed from a high density plasma may be used to form a barrier layer having improved oxygen and moisture barrier properties relative to a barrier layer formed from a lower density plasma having the same thickness. In addition, the one or more barrier layers formed by the lower density plasma may help reduce stress misalignment between the barrier layers and the buffer layer between the plurality of barrier layers. This reduced stress imbalance may help prevent encapsulant cracking when the OLED device is subjected to external stresses, such as bending. Thus, an enclosure comprising one or more barrier layers formed by a high density plasma and one or more barrier layers formed by a lower density plasma may result in an enclosure with improved oxygen and moisture barrier properties and improved durability in response to external stresses relative to an enclosure comprising barrier layers formed by only a high density plasma or a lower density plasma.

While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A method of encapsulating an Organic Light Emitting Diode (OLED), comprising:

generating a first plasma in a process chamber, the first plasma having at least 10 ¹¹cm ^-3Wherein an OLED device is positioned within the process chamber, the OLED device comprising a substrate and an OLED formed on the substrate;

pretreating one or more surfaces of the OLED and the substrate with the first plasma;

depositing silicon and nitrogen comprising over the OLED by generating a second plasma comprising silicon and nitrogen in the process chamberThe second plasma having a first barrier layer of at least 10 ¹¹cm ^-3The second plasma being generated after the first plasma;

depositing a buffer layer over the first barrier layer; and

depositing a second barrier layer comprising silicon and nitrogen over the buffer layer by generating a third plasma comprising silicon and nitrogen in the process chamber, the third plasma being generated after deposition of the buffer layer.

2. The method of claim 1, wherein the third plasma has a plasma density of at least 10 ¹¹cm ^-3Electron density of (2).

3. The method of claim 1, wherein the first barrier layer is spaced apart from the second barrier layer in a first direction, the first barrier layer having less than the second barrier layer in the first direction Is measured.

4. The method of claim 1, wherein

The first barrier layer is spaced apart from the second barrier layer in a first direction,

an encapsulant comprising the first barrier layer, the buffer layer, and the second barrier layer has less than 1x10 ^-4g/m ²The water vapor transmission rate of day is,

the enclosure has less than in the first direction Of total thickness of

The first barrier layer has less than in the first direction

Thickness of。

5. The method of claim 1, wherein

The second plasma and the third plasma are each formed using a microwave plasma source, an inductively coupled plasma source, or an electron cyclotron resonance plasma source.

6. The method of claim 1, wherein the first plasma comprises nitrogen.

7. The method of claim 1, wherein the substrate comprises a polymeric material and the first plasma comprises argon.

8. The method of claim 1, wherein the substrate comprises a glass material and the first plasma comprises ammonia.

9. A method of encapsulating an Organic Light Emitting Diode (OLED) device, comprising:

generating a first plasma comprising silicon and nitrogen;

depositing a first portion of a first barrier layer comprising silicon and nitrogen over the OLED using the first plasma;

generating a second plasma comprising silicon and nitrogen; and

depositing a second portion of the first barrier layer comprising silicon and nitrogen over the first portion of the first barrier layer using the second plasma, wherein the first plasma and the second plasma differ in density by at least a factor of 100.

10. The method of claim 9, further comprising:

depositing a buffer layer over the first barrier layer; and

depositing a second barrier layer over the buffer layer.

11. The method of claim 10Wherein the first barrier layer is spaced apart from the second barrier layer in a first direction, and the first barrier layer including the first portion and the second portion has less than the first barrier layer in the first direction Is measured.

12. The method of claim 11, wherein

The first barrier layer is spaced apart from the second barrier layer in the first direction,

an encapsulant comprising the first barrier layer, the buffer layer, and the second barrier layer has less than 1x10 ^-4g/m ²A vapor transmission rate of day, and

the enclosure has less than in the first direction

Of the substrate is described.

13. The method of claim 10, wherein

The first plasma has a plasma density of at least 10 ¹¹cm ^-3Electron density of (A) and

the second plasma has a density of about 10 ⁹cm ^-3Electron density of (2).

14. The method of claim 9, wherein the first plasma is generated in a first process chamber and the second plasma is generated in a second process chamber.

15. A method of encapsulating an Organic Light Emitting Diode (OLED) device, comprising:

generating a first plasma comprising silicon and nitrogen in a first process chamber;

generating a second plasma comprising silicon and nitrogen in a second process chamber;

depositing a second portion of the first barrier layer comprising silicon and nitrogen over the first portion of the first barrier layer using the second plasma, wherein the first plasma and the second plasma differ in density by at least a factor of 100;

depositing a buffer layer over the first barrier layer in a third process chamber; and

depositing a second barrier layer over the buffer layer in a fourth process chamber, wherein the first process chamber, the second process chamber, the third process chamber, and the fourth process chamber are arranged around a single transfer chamber.